diff --git a/src/vnet/dev/counters.c b/src/vnet/dev/counters.c
index 0a1e0a7..d02839d 100644
--- a/src/vnet/dev/counters.c
+++ b/src/vnet/dev/counters.c
@@ -54,7 +54,7 @@
 {
   for (int i = 0; i < cm->n_counters; i++)
     {
-      cm->counter_start[i] = cm->counter_data[i];
+      cm->counter_start[i] += cm->counter_data[i];
       cm->counter_data[i] = 0;
     }
 }